msgpack5: Decoding negative int64 values mutates the input buffer

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-107296
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-08 17:17:15 UTC
Updated2026-10-08 20:48:36 UTC
Descriptionmsgpack5 is a msgpack v5 implementation for node.js and the browser. Prior to 6.1.0, decoding a negative signed 64-bit integer modifies the corresponding bytes in the caller-provided input buffer while computing the value. Applications that retain or reuse encoded input for integrity checks, logging, or later processing can observe silently corrupted data, while positive integers and other MessagePack value types are unaffected. This issue is fixed in version 6.1.0.

Risk And Classification

Primary CVSS: v3.1 3.7 LOW from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Problem Types: CWE-471 | CWE-471 CWE-471: Modification of Assumed-Immutable Data (MAID)

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary3.7LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
3.1CNADECLARED3.7LOWCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Mcollina Msgpack5 affected < 6.1.0 Not specified

References

ReferenceSourceLinkTags
github.com/mcollina/msgpack5/security/advisories/GHSA-qw35-55vc-rhgj [email protected] github.com
github.com/mcollina/msgpack5/releases/tag/v6.1.0 [email protected] github.com
github.com/mcollina/msgpack5/commit/82b70393a824e1088a45a377548d1d9ab82f... [email protected] github.com
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